Clean a range hood filter by boiling a large pot of water, adding 1/2 cup of baking soda to the pot slowly and placing the filter in the pot to boil. The grease from the filter floats to the top of the water. Rinse the filter with more hot water.
For owners who prefer to clean the filter without using boiling water, automotive degreaser cuts through the grease buildup. Choose a water-based degreaser and immerse the filter in a sink of hot water. Add the degreaser and allow the filter to soak a few minutes. Rinse the filter, allow it to dry, and replace it on the range hood.
If the filter remains greasy after these treatments or has other damage, hardware stores offer replacements for most models. They range in price from $12 to $20.
These methods work for the aluminum filter found on range hoods that vent to the outside. Hoods that vent the air back into the home have an additional charcoal filter to remove odors and grease from the air. Owners should not attempt to clean and reuse these filters. As of 2015, replacement charcoal filters are available at Ace Hardware for between $17 and $28 each. They require regular replacement.